Modulation Circuit, Driving Circuit and Output Method

1. A modulation circuit that outputs a modulation signal, said modulation circuit comprising: a memory circuit that stores waveform data that determines a time width of a portion having a predetermined amplitude value of the modulation signal in advance; and a circuit that generates the modulation signal based on the waveform data and input gradation data, wherein the waveform data includes (a) data that determines a timing of start of a control operation to perform a transition from another amplitude value to the predetermined amplitude value, and (b) data to determine a timing of start of a control operation to perform a transition from the predetermined amplitude value to another amplitude value.

2. A modulation circuit according to claim 1 , wherein each of a plurality of modulation signals respectively corresponding to a plurality of the gradation data with different values has the portion which is adjusted to the predetermined amplitude value, and wherein the waveform data is referred to in order to determine the time widths of the portions of the modulation signals.

3. A modulation circuit according to claim 1 , wherein the gradation data includes data that determines a timing of start of a control operation to make an amplitude value of any one of portions of the modulation signal fall.

4. A modulation circuit according to claim 1 , wherein the waveform of the modulation signal has a portion controlled to have a stepped form, and the waveform data includes information that determines the form of the portion controlled to have the stepped form.

5. A driving circuit comprising: the modulation circuit according to claim 1 ; and a data output circuit that converts an input signal into the gradation data, wherein the modulation circuit and the data output circuit are provided on different substrates from each other.

6. A modulation circuit that outputs a modulation signal, said modulation circuit comprising: a memory circuit that stores waveform data that determines a time width of a portion having a predetermined amplitude value of the modulation signal in advance; and a circuit that generates the modulation signal based on the waveform data and input gradation data, wherein the waveform data includes data that determines the time width of the portion from a timing of start of a control operation to perform a transition from another amplitude value to the predetermined amplitude value, the timing being determined by the gradation data.

7. An image display device comprising: the modulation circuit according to claim 6 ; a plurality of scanning wirings; a plurality of modulation wirings to which modulation signals are supplied from the modulation circuit; and a plurality of display elements that are connected in a matrix fashion with the plurality of scanning wirings and the plurality of modulation wirings.

8. A television apparatus comprising: the image display device according to claim 7 ; and a tuner that is capable of selecting television broadcasting signals, wherein image display is performed based on signals output from the tuner.

9. A method of generating a modulation signal, said method comprising the steps of: inputting gradation data to a modulation circuit, the modulation circuit having a memory circuit that stores waveform data that determines a time width of a portion having a predetermined amplitude value of the modulation signal in advance; and generating the modulation signal based on the waveform data and the input gradation data in the modulation circuit, wherein the waveform data includes (a) data that determines a timing of start of a control operation to perform a transition from another amplitude value to the predetermined amplitude value, and (b) data to determine a timing of start of a control operation to perform a transition from the predetermined amplitude value to another amplitude value.

10. A modulation circuit configured: to generate a first modulation signal corresponding to first gradation data with a predetermined value so that the first modulation signal has a waveform in which an amplitude value of a portion to be adjusted to the maximum amplitude value in the waveform becomes an amplitude value Vk, which is the lowest value among the amplitude values that the modulation circuit can output, and to generate a second modulation signal corresponding to second gradation data with a value greater than the predetermined value by 1 so that the second modulation signal has a waveform which includes a first portion to be adjusted to the amplitude value Vk and a second portion to be adjusted to an amplitude value Vk+1 (Vk<Vk+1), the second portion being located in a position other than beginning and end of the waveform of the second modulation signal, the first portion having a time width equal to or greater than a time width of the portion to be adjusted to the amplitude value Vk in the waveform of the first modulation signal.

11. A modulation circuit according to claim 10 , configured to generate a modulation signal corresponding to gradation data with a value greater than the value of the second gradation data by N (N>=1) so that the modulation signal has such a waveform that a time width of the second portion to be adjusted to the amplitude value Vk+1 in the waveform of the second modulation signal is increased by N times width of unit time of time width control.

12. An image display device comprising: the modulation circuit according to claim 10 ; a plurality of scanning wirings; a plurality of modulation wirings to which modulation signals are supplied from the modulation circuit; and a plurality of display elements that are connected in a matrix fashion with the plurality of scanning wirings and the plurality of modulation wirings.

13. A television apparatus comprising: the image display device according to claim 12 ; and a tuner that is capable of selecting television broadcasting signals, wherein image display is performed based on signals output from the tuner.

14. A method of outputting a modulation signal, said method comprising the steps of: outputting a first modulation signal corresponding to first gradation data with a predetermined value, the amplitude value of a portion to be adjusted to the maximum amplitude value of the waveforms of the first modulation signal being adjusted to a amplitude value Vk that is the lowest amplitude value among amplitude values that the modulation circuit can output as the amplitude values of modulation signals; and outputting a second modulation signal corresponding to second gradation data with a value greater than the predetermined value by 1, and having a first portion to be adjusted to the amplitude value Vk and a second portion to be adjusted to a amplitude value Vk+1 (Vk<Vk+1), the second portion being located in a position other than the front edge and the rear edge of the waveform of the second modulation signal, the time width of the first portion being equal to or greater than the time width of the portion of the first modulation signal to be adjusted to the amplitude value Vk.

15. An image display device comprising: the modulation circuit according to claim 1 ; a plurality of scanning wirings; a plurality of modulation wirings to which modulation signals are supplied from the modulation circuit; and a plurality of display elements that are connected in a matrix fashion with the plurality of scanning wirings and the plurality of modulation wirings.

16. A television apparatus comprising: the image display device according to claim 15 ; and a tuner that is capable of selecting television broadcasting signals, wherein image display is performed based on signals output from the tuner.

17. An apparatus that generates a modulation signal in which an amplitude value and a time width of the amplitude value are controlled in accordance with input gradation data, said apparatus comprising: a control circuit; and an output portion, wherein the control circuit is a control circuit configured to specify a maximum time width which is a maximum value of a time width of a first amplitude value, and wherein the output portion is an output portion configured: (a) to output the modulation signal in which the time width of the first amplitude value is controlled so as to be a time width corresponding to the input gradation data which is shorter than or equal to the maximum time width, when the input gradation data is smaller than or equal to a predetermined value; and (b) to output the modulation signal in which (i) the time width of the first amplitude value is controlled so as to be the maximum time width in a first period and (ii) a time width of a second amplitude value is controlled so as to be a time width corresponding to a difference between the input gradation data and the predetermined value in a second period different from the first period, when the input gradation data is greater than the predetermined value.

18. An image display device comprising: the apparatus according to claim 17 ; and an image display unit having a plurality of display elements.

19. An image display device according to claim 18 , wherein the display element has an electron emission element and a fluorescent body which emits light by irradiation of electrons emitted from the electron emission element.

20. A television apparatus comprising: a tuner for a television broadcasting signal; and the image display device according to claim 19 , which displays an image based on signals output from the tuner.

21. A modulation circuit that outputs a modulation signal, said modulation circuit being configured: (a) to output the modulation signal in which a time width of a first amplitude value is controlled so as to be a time width corresponding to input gradation data which is shorter than or equal to a predetermined time width as an upper limit, when the input gradation data is smaller than or equal to a predetermined value; and (b) to output the modulation signal in which (i) the time width of the first amplitude value is controlled so as to be equal to or greater than the predetermined time width in a first period and (ii) a time width of a second amplitude value is controlled so as to be a time width corresponding to a difference between the input gradation data and the predetermined value in a second period different from the first period, when the input gradation data is greater than the predetermined value.